NEW DELHI (Reuters) - India is liaising with other emerging-economy countries on a plan to co-ordinate intervention in offshore currency markets blamed for worsening a currency rout over the past three months, a senior Indian finance ministry official said on Friday.

The idea of major emerging economies taking action together to offset the impact of a stronger U.S. dollar as the Federal Reserve reins in its stimulus had also been floated in June by Brazilian President Dilma Rousseff in a phone call to her Chinese counterpart.

The leading emerging market nations that form the BRICS groups - including Brazil, Russia, India, China and South Africa - fretted about the global turbulence at a July G20 summit in Moscow, but no action materialized. G20 leaders are due to meet in St Petersburg next week.

“It is now time to stop,” Dipak Dasgupta, the Indian finance ministry’s principal economic adviser, told Reuters, referring to speculative behavior in offshore markets he said was damaging the stability of the world economy.

“It is going to happen in a matter of days rather than weeks,” he said. “Brazil and India can start the move.”

He said there had been correspondence among several countries on the plans in the last few weeks and predicted that action would now come quickly, but he declined to share specific details of the discussions.

Dasgupta said the conversations were not limited to BRICS nations. It was not immediately clear how many takers there were for such a proposal from other major emerging economies.

However, Brazil’s central bank said it was not currently participating in any planning for co-ordinated intervention in offshore markets.

“There is no initiative like that,” a Brazilian central bank spokesperson said.

Still, the comments from the Indian official extended the rupee’s gains on Friday to 65.72 per dollar from 65.85 after the currency slumped to a record low earlier this week. The government in New Delhi is struggling with the weakest economic growth in years and a yawning current account deficit.

The sell-off in emerging markets has been driven by concern about the end of cheap dollars from the U.S. Fed’s stimulus program, prompting a massive capital flight toward dollar-denominated assets. The rout has been compounded by short-seller attacks in offshore trading centers.

When the idea for coordinated action surfaced earlier, analysts said that - unlike their wealthier counterparts at the G7 group - the BRICS were still far from either coordinating monetary policy or jointly intervening in forex markets.

Separately, the BRICS countries have been working during the past year on a $100 billion reserve fund and a joint development bank to reshape the global financial architecture long dominated by rich nations. These new institutions are expected to take some time to materialize.

“NO FORCE CAN STOP THEM”

Offshore markets developed to allow foreign investors to hedge or speculate on emerging-market currencies when exchange controls in those countries made it difficult to trade directly in the domestic spot market.

Dasgupta said such markets had exerted pressure on 12 of the main emerging market currencies, including Brazil, China, India, Russia, South Africa, Turkey and Malaysia.

He said that, acting together, even four or five members would have estimated international reserves of $1.2 trillion. With China, the total reserves exceed $6 trillion, he said.

“Once they decide they will move to intervene to mutually support each other to put a floor, there is no force that can stop the impact,” he said.

The rupee is the worst performing major currency in recent months, having lost about 20 percent against the dollar since May.

Non-deliverable forward (NDF) markets operating mainly from Singapore, Hong Kong, New York and London allow trade in several Asian currencies, including the rupee. They allow investors to bet without ever having to physically exchange the currency involved.

A report by the Indian central bank in August said NDFs were affecting the rupee’s value. Indian central bank Governor Duvvuri Subbarao in July said he would rather there were no NDF markets.

One Indian government estimate puts global trading of the rupee at $60-$70 billion per day. By that yardstick, authorities believe they would need fire-power of $6 billion to $7 billion per day to intervene and make a dent in the offshore currency markets. Officials say that is beyond India’s reach alone.

Writing by Frank Jack Daniel; Editing by John Chalmers and Neil Fullick